Structural slide-rule.



P ATLNTLD MAY 12,1908. J.v L. HALL. STRUCTURAL SLIDE RULE. APPLIUATIONFILED 00T. 12, 1907. 2 SHEETS-SHEET 1 f W/TNESSES 6.1- A,

BY A TTOHNEYS No. 887,890. f -PATENTLD MAY 12, 1908.

J. L. HALL. STRUCTURAL SLIDE RULE.

APPLICATION FILED 00T.12.190"I.

2 SHEETS-SHEET 2.

' /NVENTOH y@ :z BY

A A TTOHNEYS the di'll'erent faces which is preferably in the form of atri- JOHN L. HALL, or New YORK, N. Y(

STRUCTURAL SLIDE-RULE.

v No. 887,390.

Specification of Letters Patent.

Patented May 12, 1908.

v Applic-ationiled October 12, 1907. Serial No. 397,093.

To all whom it may concern.'

Be it known that I, JOHN L. HALL, a citizen of the United States, andresident of New York, in the county -and State of New York, haveinvented certain new and useful Improvements Relatin(r to StructuralSlide- Rules, of which the following is a specification, taken inconnection with the accompanying drawings.

l y invention relates to structural slide rules andl more particularlyto, first, the

mechanical construction of vsuch a rule, and,

second, the co-location of certain scales upon of thestructural'sllde-rule,

angular rule so as to enable a person familiar with such instruments ofprecision to solve mechanically and quickly problems arising in theerection of buildings, bridges, and so forth, without the necessity ofresorting to complex and intricate solutions.

Upon the three faces of the triangular-rule diflerent scales andarrangedv I have placed slides so that after computing mechanically onone face of the rule the. slide can be'left in that position whileanother problem is mechanicallysolved on another face without to thesimilar parts in the Figures 1, 2, and 3 are side elevations of thechanging or altering in an particular the elative location of the side'on the iirst ace.

By my invention I have reduced an instrument of precision equa ly fitfor a triangular, engineering or architectural scale and a complex sliderule. Furthermore, by interchanging the slides upon the respective facesof the rule other intricate problems may be ,solved mechanically, asWill later be pointed out.

In the accompanying drawings, showing an illustrative embodiment of thisinvention, in which the same reference numerals refer several figures.

three faces of my structural slide rule. Figs. 4, 5 and 6 are sideelevations of the face of my rule shown complete in Fi 2 ,the slidebeing adjusted to different posit1ons to better illustrate its use insolving certain problems hereinafter referred to. Fig. 7 illustrates ascale on the back of the slide shown in Fig. 1. Fig. 8 shows a scalev onthe back of the slide in Figs. 4, 5 and 6. Fig. 9 is a scale ,on theback of the slide shownA 1n Fig. 3. cross-section. vof the structuralslide rule showing the preferred form. Fig. 11 is a cross-sectionshowing a modified form. Fig. 12 is a cross-sectionshowing la stillfurther. modified form. Fig. 13 is a erossssection, the slides beingomitted, of a still further form.

Structure of the rule-In the illustrated embodiment of the inventionshown in the drawings, 1 is a triangular slide rule having three faces,2, 3 and 4, illustrated respectively in Figs. 1, 2 and 3 of the drawing,see

also Fi 10. In the preferred form, the trian u ar rule consists of acorel 6 having Fig. 1() is a y 13 in the core, three such screws 'beingl preferably used to hold each rismatic flange 8 to its respective seat7 on t e core 6. 'lhe holes 13 are -preferably of `at least twodiameters, the lar yer being adapted toreceive the head of t e screw.

Any suitable yielding medium, such as a coil' spring` 14, preferably acompression spring, one end of which bears against the headof the screwand the other against thel bottomof the hole` 13, may be used, thearrangement preferably being such that there arene screw threads uponthe portlon of the shank passing vthrough the smaller ortion of the hole13, so that the p'rismatic ange 8 maybe held yieldingly to its seat 7 bymeans of the screw and spring to coinr pensate for contraction andexpansnan. This ad`ustment permits the use of tight fitting slideswithout their binding in the grooves. To insureabsolute alinement Ireferably bore the holes 13 in the core liefore the flange is sawedfromit. Within each face of the'rule I locate slides 15, 16T and 17,respectively, mounting them .in any suitable manner so that theycanreadily slide within the respective faces of the rule. The sides of theprismatic ianges and the faces of the slides are flush and make a neatand attractive triangular slide rule and one which can be placer flatupon` any desired work so that in addition te its uses hereinafterreferred to, it performs'theordinary function of atriangular rule.

There are various. Ways` of mounting the V core 6 with relation to theprismatic flanges,

while in Fig. 13 the e from one piece of material, b ut in both flangesare shown connected to the core by v referably for the sake of cheameans of splints 18,- 18. The contours of the core and flanges may vary,but all such' constructions come underthe terms of m invention.

e all the parts of my' structural slide rule may be made out of wood,metal, or any other suitable material, or the rule may rbe made partly.of metal, and partl as for instance, the flanges may of metal and theslides of wood, or vice-versa, I

ness in manuacture, and for lightness of my slide che m e all the parts-i'ule out of Wood, preferably wood, althouh it is to be understood'that am not at all mited to such material. .Upon the different faces andslides, I secure in any suitable manner scales which may be eitherimpressed or engraved directl made or, as is common, the scale may befirst engraved upon plates and the printed scales from such latessecured in any suitable manner to t e faces and slides of the rule,being before or afterwards waterproofed with some transparent medium, asis usual. Scalea-These different scales I have desinated bithe4 letters.A, B, C,D E, F, G, K, L, N, and P, respectively; the scales A, B C, Dbeing upon face 2 of m structural slide rule, the scales E F, G, uponface, and scales K, L, M I,upon face'4,-all as clearly shown in 1Ato 3,inclusive. Scales B, C, D comprise the ordinary logarithmic scales, theuse of which 1s a matter of common knowledge among so that it is notnecessaryto go eineers, y into this matter other than to point out lthaton the surface of the core 6, the saine being the 'bottom of the troughbetween the two rismatic flanges 8, 8 which form guides for t eslide,15, I refera ly place a key, the use of which is we known amongengineers,

Direct Slide.

a s b y 9 10 v B' l barv a :c` "ha, a z b'z a z 1 1:- v-J .i Iz, 1 L `aD y b the aremitered -isting Figs. 12and 13 thel of wood,

` terminemechanicall The scales A, B, C, D compute mechanically the safeload which can be carried. t

on me s I'mmge he mi@ E which is oil 'one of the prismatic flanges, andscales F, G upon the shde 16; the scale H being upon the face of thecomplementary prismatic ange 8'. This expression -1- signifies theratioexy between the unsupported length l and the radius of gyration r of acolumn, post, strut, or compression member. This ratio in some `formenters into all formulas roposed by engineers to determine square mch ofsectional area thatl acolumn will safely carry. The formula in 'which Sre resents the safe load per uare inch o the sectional area of' the coumn, is such a formula and is shown on scaleII near the extreme left ofFig. 2. To find the value of S for any s ciic case, it is necessary tosubstitute the wn values of l and r and solve the equation. Withoutgiving examples of such equations and the in tricate computationswhichhave to be entered into'for their solution, it may be said that bymy invention Iam enabled to save all the exhausting calculations bygiving the upon the material of which the slide rule 13s.' resultsmechanically upon my structural sliderule. In Fig. 4 I have shown thisface of my structural slide rule with sufficient rtions of the differentscales'shown so as to ustrate its use. Keeping in mind the expression ascale of-l hs (l) is placed on the upper flange of the e' a scale ofradii of ation (r) immediatel underit on the s de; a scale of loads in tousands of pounds isplaced on the lower flange, an' to one another thatwhen the given radius of ation (103.4 is brought directly under gg; 'venlength (l) 12 9 then the allo w able oad per s?. in. (S) 12590 lbs. willbe indicated on the ower scale by an arrow which is on the slide.

In Fig. 5, I have shown another adjustment of the slide 16 to solvemechanically another problem. yIf any two of the factors,

r, l or S be given the third is readily found by my invention. Themethod of fin S has alreadybeen `ven. Now, su poseitis to know the eastradius o gyration which a columnlO ft. long could have and safely carry10,000 lbs. gt si. in. aecordingto the above formula. t t e arrow at 10on the y `lower scale, and under 10 on the upper scale, readAthe resulton scale just below=n 1.34.

With scales E, F, G, H, I am also able to deand expeditiously the l,.lengthsf clclumqr a e to carry e a am .y i 1 to atest imsupgorte ve andbe load. Suppose, for instance, itis d these scales are so related.

'lis

theloa per ioo esired 'A the use of the scales structural rule I haveplaced a n examples are merely given to show the use of the scale andhow simply and quickly any problem confrontin an architect or personusing the scale cane solved. To assist in upon this face 3 of my A keyon the core 6, the same forming the bottom of the trough lying betweenthe two prisinatic flanges upon which lare. mounted the scales E and ll,said key being visible when the scale 16 is moved, for instance, to theright, as iii Fig. 4, when the following s inbols which are readilyunderstood b al architects and draftsmen become visi le. v

E ja', l se l .37 y ii.

, M F y s r 1 r "l l r F L* 1| G ,i i J t G H I l y 8 y. .s H

The remaining face 4.of the slide rule is illustrated `rin Fig. 3, theslide 17 being slightly drawn to the right tol illustrate the use of thescale in a problem .hereinafter mentioned, and also to show thev keywhich, as in the other'i'aces, is located in the trough lying betweenthe scales .K and P, respectively, on the prismatic flanges 8, 8. Onthis face are represented scales K, L, M, N, and P, and unlike in theother faces there are two slides adapted for relative movement on thisside of t ie rule for use in solving problems to be hereinaftermentioned. In building operations, particularly in the modern*fire-proof building, the area is usually laid out in rows of columns soas to divide the ground plan into rectangular panels, each panel beingbounded by four columns. It is absolutely necessary that the beams beplaced close enough together to insure safety, but they should not becloser than necessary -'$0 Cillly' the required load,'for such would bean exi pensive waste of material. It is therefore necessary in theplanning of these buildings, or in the planning of. any other structuralwor to try out different schemes'and make numerous calculations todetermine the proper; spacing of the beams or channels so as to obtain aperfectly safe structure with the required factor ofsafety, but still touse a minimum amount of material.

By the use of my invention, I have ymade it the slide 16 carrying thescales on scale F which will,

The vertical lines place a logarithmic scale L on tures to obtain in afew seconds mechanically the exact size of beams or channels, togetherwith their weight which would under any given condition.

On the upper ortion of the face 4, Fig. 3, I place a scale of channelsand vI-beams upon the prisinatic flange in which the numerals 3, 4, 5,6, etc. in bold type represent the depth in inches of channels andI-.beanis 20 turned up from the horizontal lines 21, Fig. 3, representthree-inch channels weighingy respectively 4, 5, and 6 poundsper vlinearfoot. The vertical lines immediately following the ones last describedand shown in connection with the 4numeral 4 represent channels 4 inchesdee weighing respectively 51, 6i and 7i poun( s Aper linear beyrequired,

foot and so on up the scale, the numerals in l bold type representingthe de th, either of channels or beams in inches andp onthe linesextending upward from the line corresponding to line 21 representing theWeight per linear foot for channels of Ythat depth.V l p '.With each ofthe numerals 3, 4, 5,' 6, etc, in bold type, there is another horizontalline 24 with downwardly extending vertical lines which, after numeral 3,are designated 5.1., 6% and 75- respectively, and after the numerals 4,7%, 85, 9% and 10%, respectively, many of the lead lines being omittedso .as not tofconfuse the drawing at this point. These downwardlyextending vertical lines ie resent the weight per linear foot ofbeams tiree inches dee four inches deep, five inches deep, etc., so t iat by myinvention I associate with each one of the numerals 3, 4, 5, 6, etc.characters or numerals which will show at a glance the weight'per linearfoot of either a channel or I-beamJ lof a certain depth.

Immediately under the fixed scale K, I

p the upper portion of the plural slide 17 which represents Varied span'lengths of beams from 3 4 to On the bottom flange I place a logarithmicscalel P-re resenting various loads per square foot o `floor surfacefrom one pound per square foot to 100() pounds and immediately-abovethis scale P, onthe lower surface of the lural slide 17 I place alogarithmic scale N representing various spaeings of beams from 8/10thsof a foot to 800 feet. Between the scales L and N and upon thepluralslide 17 I locate an auxiliary logarithmic scale M to be used in iindingthe end reaction.. Though in the usual operation of my inventionV thetwo portions'of the numeralsslide 17 move as one slide, they arecapable,` y

however, of relative movement for thefollowing purpose.` If th'e numberson scale l be seen that 16,00() of P isopposite 5() of scale N.' In.other words. 5() of scale N be considered to represent thousands, itwill l marks the extreme fiber stress on scale P. If we wish to figurethe beams or channels for any other extreme fiber stress, as, for inore,giving results corresponding to the desired extreme fiber stress. Toshow how this scale is used I have in Fig. 3 shown the slide 17 drawn tothe' ri ht so as to bring 6 feet on the spacin scale over 250 pounds therequired loa per s uare foot on scale P and feeton the scaleL, a mereglance at scale K will determine instantly that given these conditionsit will be'necessary to use an I-beam 12 inches deep. and 31 1/2 poundsper linear foot. This one example is merely given for it is thoughtthatsuiicient has been said to show hofw with any three of the conditions(span, spacing, we' ht tol becarried, size ams), llnvn, tiltsa olrthcal; alwlalys blfounqk the e ort iso' o suc ro ems Aing locyated in the,vtlrlbg h l pbetween scales K and P, said ke 'being part y shown inFig.

right sniiiciently to show merely a rtion of An instance of the use ofthe auxiliary scale M to find the reaction R may be given as follows:Under the length 16 note the reading 125 on scale M; then under the samereading 125 on scale N find the requiredreaction, 12,000 pounds on scaleP, seeFig. 3.

` The remaining o ration to find the bending moment in a gir er12,000x5-1/2==66,000 is performed mechanically on the scales A, B, .v

or C, D, the use of which is generallyunderstood, the girder having twosuch beam re' actions at\points 5-1/2 feet from its ends, thus creatinga bending movement of 66,000 foot pounds. e

The scale P is sodesigned in its relation to the other scales that itrepresents (1) loads per square foot in pounds, (2) reactions inthousands of pounds, (3) moments of resistance, or bendinlmoments inthousands of foot pounds. T 's last function enables the user to findthe der required in the aboveproblem thus: ectly opposite the knownbending moment 66,000 on scale P,

' we find the required girder on-scale K, viz:

12" I-beam 50 pounds per linear foot, orV a 15" channel 45 pounds perlinear foot. As a 15 I-beam 42 pounds per linear foot, to

lthe right of the numeral 12, is a" stronger beam and of lighterWeight,it would probably be chosen by the designer of the structure.With a greater number of .variable uantities on this face 4 of 'mystructural s 1de rule as compared with lthe column slide rule acorrespondingly greater number of problems are capable of mechanical'solution y the beam or channel slide rule alone on this face 4 of myrule, or in conjunction with a general slide rule. Given any three ofthe factors, (1) size of beam or channelv (2) span 'in feet, (3)spacingin feet, (4) u crm load per s uare foot, the fourth is readilyfound.

he iffrent slides, 15, 16, v17 areV interchangeable and solutions forawide range of roots of'numbers may be had scales K-P, we have thefollowing solutions, and many more: v

' VP17;I l-17e 1f slide 1-7 be ipleerted between eeeleeA-o, we'haveamong others the following: A

one half of the slide so that by comparison problems involvngthefollowing powers and A @mueve-Ale 10) P14-FAIonbeekefeeelecehewninrig-sene meh and one foot are eachA decimallydivided on.' 115 3 where the sli e 17 has been drawn to the 3 Ferineteneejif ende 15fbe inserted between 5 or core', and one or with thefractional divisions o posite on the other half, it is easy to find) thedecimal equivalent of any fraction of an inch or foot or vice versa.

Having described this invention in oo nnection with illustrativeembodiments thereof, to the details oi which disclosure the in--solution of different problems ada ted to be solved by the scales, saidkeys eing normally located beneath the slides and visible when theslides are drawn out.

2. A triangular slide rule including co' erating scales and formed of acore or bod)y portion and flanges or edges independently detachable fromthe core or body portion.

3. A triangular rule formed of'a core or body portion, flanges lor edgesindependently detachable from the core or body' portion, and means toyieldingly hold the edges or flanges to the body portion.

4. Arule consisting of a core or body por tion, a seat formed on thebody portion, an edge or flange having a portion to cooperate with theseat and means for ieldingly holding the flange to the seat saidY meanspermitting lateral movement of the edge inaddition to the yielding`movement.

5. A rule consisting of a core or body portion, a seat formed on thebody portion, an edge or flange having` a portion to cop'erate with theseat and means for yieldingly and adjustably holding the flange to theseat.

6. A triangular rule formed of a body or core, a plurahty yof edges orflanges supported by the bod ortion and slides mounted in the faces 'o't e triangular rule, the face lof said slides being flush With thesurfaces of the edges or flanges.

7. A triangular slide rule formed of a body or core and two or moreedges or flanges detacliable from the core and means for yield! inglyholding the flanges or edges to the body portion;

8. A triangular rule formed of a-body or core and two or more ed es orflanges detachable from the core and means for yieldingly and adjustablyholding the flanges or edges to the body portion.

9. A triangular rule having a body portion or core, one" or more seatslformed on thebody more detachable edges or flanges each edge or fl ehaving -a ortion to co erate with one dfntghe seats on t e core orbo yportion, and means for yieldingly securin the flan e or edgle to thecore.

10. `trian ar rule a body por a tion or core, one or more seats formedon the Ybody or core and one or more detachable edges or flanges eachedge or fla e having a portion to cooperate with one of t e seats on thecore. or body portion, means for yieldingly securing-the flange or ed eto the core, and one or lmore slides mounter in the face or faces of therule and adapted to be guided by said flanges or edges.

11. A triangular rule'having a body ortion or core, detachable flangesor edxges, means for securing them to the body or core, and a pluralityof slides mounted on different faces of the rule, two of them mounted onone face of the rule, and adapted for relative movement with relation tothe flanges and to each other.-

12. A triangular rule having a bod portion Lor core, one or more holesin sai body portion, one or more detachable flanges or edges, one ormore screws mounted Within hole, and taking vinto the detachable edge orflange, and one or more s rings mounted within the holes, one in, eachole, and acting on the head of the screw and the bottom of the hole toyieldingly and adjustably hold the flange or edge to the core or bodyportion.

13. A triangular sliding rule having a core or body portion and one ormore edges' or flanges and means to adjust the flange or edge to thebody portion to compensate for expansion and contraction or cent parts.v

14. A triangular slide rule having o'n one face, a plurality of scalesrepresenting load per square foot, spacing, span in feet, and numeralsor marksA designating structural material, the respective scales beingada ted 'to be moved to solve mechanically prob ems involving (l) sizeof beam channels or other structural material, (2) span in feet, (3)spacing in feet, or, (4) uniform load per square foot when any three ofthem are given the'scales on the different faces being adapted to beoperated `independently of each other.

15. A structural slide rule having on one face, a plurality of scalesrepresenting load per square foot, s acing, span in feet, and numeralsor mar s on scale designating structural material, the respective scalesbe- 'ing adapted to be ically roblems involving (1) size of beam span infeet, (3) spacing in feet, or, (4) uniform load them are given, and anauxiliary logarithmic scale to find the end reaction the scales on thedifferent faces being adapted to be operated independently of eachother.

16. A triangular slide rule having scales on kits different faces,"saidscales being adap'ted the different-holes in the core,'one in eachy Wearof adjamoved to solve mechanchannes or other structural material, (2).

per square foot when any three of to be operated independently of eachother. v

. slide rule, and upon the third lface a 17. A structural slide rulehaving u on one face the ordinaryr slide rule, upon anot er face anindependently operative column channel slide rule operativeindependently of the othersl 18.v A structural slide rule having u onone face the ordinary slide rule, upon anot er face an inde endentlyoperativecolumn rule, and upon t e third face a beam or channel slideruleoperative independently of the others, the sli es upon one or moreof the faces being adapted to be used in connection with scales upon aface oi the rule other than that witg which they are normally meant tobe use 19. A structural slide rule having upon one face the ordinaryslide rule,

. face an independently operative column representing load er squareslide rule, and u on the third face, a beam or channel slide ru eoperative independently of the others and an auxiliary scale todetermine the end reaction.

20'. A triangular slide rule having a scale desi ating or representingthe depth and wei t of structural material, an .independ- .entyoperative scale representing span in feet, a sc ale representing spacingand one foot operative in ependently of t e others.

21. A triangular slide rule having a scale desipating or re resenting'the depth and weig t per lineal oot of structural material, anyindependently operative scale representing span in feet, a scalerepresenting spacing, and one representing load r square feet, thescales representing span in feet and spacv beamor .desi ating up onanother `olperating to form ing mounted on the ing adapted to beoperated independently.

22. A triangular slide rule having-a scale 'ivig t'per lineal oot ofstructural an independently o span in feet, a sca scale representingload per scale representing span in being mounted on the sli de, and anauxiliary scale for determining the end reaction Iall the scales beingadapted to be operate independently.

23. A triangular rule plurality of edges supported by the body andprovided with scales and a plurality of slides mounted in the faces oithe rule to cooperate therewith.

24. An architects scale formed of a body or core, two or more detachableedges or flanges secured to the core, and one or more slides mounted toslide between the edges or langes, two edges or flanges cooperating toform a groove for one slide.

25. An architects scale formed `of a body or core, a plurality of edgesor flanges secured to the core, a plurality of gropvcs formed by theedges or flanges, two edges or flan es coa groove, a plura 'ty of sides, the rooves and slides being formed of substantia ly the same sizeto permit the slides bly with diiierent square foot, lthe to be usedinterchangea grooves to solve diflerent roblems.

- fJ HN L. HALL Witnesses:

HARRY L. DUNCAN, JEssLE B. KAY.

slide the scales be-- or re resenting the depth and material, erativescale representing e' representing spacing, av

feet and spacing' 50 formed of a body, a

